For example, in a belt adopted in a continuously variable transmission for power transmission, in order to bindle integrally a plurality of elements arranged circularly in laminations, a laminated ring obtained by laminating a plurality of metal rings is used.
The metal rings constituting the laminated ring are manufactured in the following way. First, both edges of a rectangular metal thin plate is welded together to form a cylindrical drum, the drum is mounted to a cylindrical drum retaining unit having a variable outer diameter. At the moment, the outer diameter of the drum retaining unit is enlarged to retain firmly the drum. Thereafter, by trimming the drum into round slices with a predetermined width, a plurality of metal rings are formed while being retained by the drum retaining unit. The retaining state is released by reducing the outer diameter of the drum retaining unit, each metal ring is detached from the drum retaining unit and transported to a post-processing step such as a grinding process or the like.
In transporting the plurality of metal rings to a post-processing step, it is necessary to extrude the metal rings one by one into a transporting passage configured to transport the metal rings to the post-processing step. If such operation of extruding the metal rings is performed by a worker manually, for example, it will be extremely troublesome and the working efficiency would be worse.
Therefore, there has been disclosed in conventional arts a technique in which the metal rings are extruded one by one by using an extruding device provided with a rotating shaft having spiral extruding grooves formed in the outer circumferential surface thereof in accordance with the width of the metal rings in the axial direction (refer to patent document 1).
In the mentioned device, the metal rings whose retaining state is released as the outer diameter of the drum retaining unit is reduced is mounted to the extruding shaft of the extruding device with the arrangement state thereof being maintained in the same axial direction, and thereafter, the extruding shaft is rotated.
According thereto, each metal ring is delivered along the spiral extruding groove, it is possible to extrude the metal rings one by one with certainty without manual operations, thereby, it is possible to improve the working efficiency.